1. Field of the Invention
The present invention relates to printers that can perform recording on both roll sheets and cut sheets, and to conveying devices included in such printers.
2. Description of the Related Art
Printers that are capable of performing recording on both roll sheets and cut sheets are known. A printer of this type has two operation modes, which are a roll-sheet operation mode and a cut-sheet operation mode. Specifically, the printer has a roll-sheet mode for cutting and discharging a roll sheet upon completion of recording performed on the roll sheet and a cut-sheet mode for discharging a cut sheet upon completion of recording performed on the cut sheet. Furthermore, the printer has a mode setting unit for setting the operation mode to one of the two modes.
However, the following problem occurs if the matching between the set mode and the actually set sheet is incorrect. Specifically, if a roll sheet is set when the operation mode is set to the cut-sheet mode, the trailing edge of the sheet cannot be detected during the discharging process, resulting in continuous feeding of the roll sheet. On the other hand, if a cut sheet is set when the operation mode is set to the roll-sheet mode, the cut sheet would be cut during the discharging process.
Japanese Patent Laid-Open No. 2000-117691 discloses a technology in which a sheet detector for detecting the length of a set sheet is provided to automatically determine whether the matching between the set operation mode and the set sheet is appropriate based on the length of the sheet (sheet length) detected by the sheet detector.
However, in the technology disclosed in Japanese Patent Laid-Open No. 2000-117691, the sheet length is detected, and if the detected sheet length is smaller than a reference value, the sheet is determined that it is a cut sheet. Therefore, if the length of the cut sheet is larger than the reference value, it would be determined that the sheet is a roll sheet even though the sheet is actually a cut sheet, possibly resulting in an incorrectly set mode. Furthermore, the aforementioned technology requires a device for detecting the sheet length and also requires enough time for detecting the sheet length. This is problematic in that the cost of the printer may increase and the time required for the sheet setting process may become longer.